Production of textile materials



Patented June 3, 1941 PRODUCTION OF TEXTILE MATERIALS Bernard Joseph Flanagan and Albert Mellor, Spondon, near Derby, England, assignors to Celanese Corporation of America, a, corporation of Delaware No Drawing. Application March 29, 1938, Serial N 0. 198,683. In Great Britain April 23, 1937 9 Claims.

This invention relates to the production of textile materials, and particularly to the production of crepe fabrics containing highly twisted crepe yarnshaving a basis of organic esters of cellulose.

Crepe fabrics may be obtained by highly twisting yarns of cellulose acetate or other organic ester of cellulose and weaving such yarns into fabric form. Crepe fabrics of especial value are obtained by forming the fabrics from yarns of cellulose acetate or other organic ester of cellulose which have been highly twisted by a process in which at least the last part of the high twist is inserted while the yarns are under the influence of steam or hot water, processes of this type being described in U. S. Patents Nos. 2,088,628, 2,088,587 and 2,089,191. On treating the fabrics produced by any of these processes with hot aqueous liquids, e. g, hot soap solutions, the fabrics shrink and acquire a crepe appearance, this crpe appearance being more pronounced in the case of fabrics containing yarns produced by the processes of the above mentioned specifications. Such treatment with hot aqueous liquids is generally referred to as the crping operation and the liquid used is referred to as the crping bath.

In order to obtain the best results the crping operation must be continued long enough to allow a considerable shrinkage of the high twist yarns to take place. It has now been discovered,

however, that the duration of the crping operation necessary in the case of fabrics containing high twist crepe yarns of cellulose acetate or other organic esters of cellulose can be considerably reduced whilst effecting at least the same amount of shrinkage or, in other words, that the rate of shrinkage of such high twist crepe yarns during the crping operation can be considerably increased, if the fabric containing such high twist crepe yarns is treated prior to the crping operation with agents having a hydrolysing or saponifying action on the cellulose ester present. Furthermore, by means of the new process it is possible to obtain satisfactory crpe effects with the aid of cellulose ester yarns which are twisted to a lower degree than is necessary to obtain similar effects if the hydrolysing treatment is not applied, e, g. 10 to 20 turns per inch less.

The treatment with the hydrolysing or saponifying agent may be such that considerable hydrolysis or saponification is effected, e. g. a loss of 20 to 30% in the weight of the materials.

Preferably, however, the saponification or hy drolysis effected is not so great as to destroy the aflinity of the materials for dyestuffs having affinity for cellulose ester materials, and very satisfactory results may be obtained if only a slight saponification or hydrolysis is effected, e. g. a saponification or hydrolysis resulting in a loss of only 1 to 3 or 5% of the weight of the cellulose ester materials.

The fabric treated may be formed entirely of yarns of cellulose acetate or other organic ester of cellulose or may be a mixed fabric containing, in addition to high twist crepe yarns of cellulose acetate or other organic ester of cellulose, crepe yarns or other yarns of regenerated cellulose (produced, for example, by the viscose, cuprammonium or nitrocellulose processes) or yarns of cotton, silk or wool. The high twist crepe yarns of cellulose acetate or other organic ester of cellulose may be contained in the warp or weft of the fabric or both in the warp and 'in the weft.. Particularly valuable results are acids, e. g. hydrochloric acid, or organic acids,

e. g, formic acid and oxalic acid. Preferably, however, strong saponifying agents are employed such as caustic alkalies and alkali metal salts of weak acids, e. g. caustic soda, caustic potash and sodium carbonate.

In general the hydrolysing or saponifying agents are applied to the fabrics in the form of aqueous solutions. The application of the solutions may be efl'ected, for example, by immersing the fabrics in the solutions or by contacting the fabrics with padding rollers supplied with the solutions. The method of applying the solutions to the fabrics is preferably such that the amount of solution carried by the fabrics can be adjusted. Thus the fabrics may be passed through nip rollers adjusted to leave the desired amount of solution in the fabrics.

After the treatment of the fabric with the hydrolysing or saponifying agent the fabric is preferably dried, though this is not absolutely necessary. It is found that, in general, not only are greater rates of shrinkage obtained if the treated fabric is dried prior to the crping operation but the total amount of shrinkage obtained is greater. The drying may be effected in any convenient manner, e. g. by passing the fabric through a chamber containing hot air or other hot gas, or by passing the fabric in contact with 5 hot surfaces as, for example, heated metal drums. The temperature of drying may vary considerably but it is found that the best results are obtained if the drying is carried out at 50 to 100 C. and preferably 75 to 100 C. The drying of the fabric is preferably effected while the fabric is under the minimum possible tension.

After such a drying operation the fabric is preferably washed with warm water or a warm soap solution, e. g. at a temperature up to 50 to 60 C. prior to the crping operation.

The optimum concentration of the solution of hydrolysing or saponifying agent applied to the fabric varies according to whether the fabric is passed direct from the application of such agent to the creping bath or is dried, or dried and washed, before being passed to'the creping bath. Thus it is found that very valuable results can be obtained by treating fabric containing high tions containing 0.5 to 3% of caustic soda, the optimum concentrations where the fabric is passed direct to the creping operation being about 1.5 to 2.5%, and the optimum concentrations .twist crepe yarns of cellulose acetate with soluwhere the fabric is dried prior to the creping operation being about 1.25 to 1.75%, the amount of caustic soda solution carried by the fabric being in each case about 80% of the weight of the fabric. In the treatment of fabric containing high twist crepe yarns of cellulose acetate with solutions of sodium carbonate in accordance with this invention, a satisfactory concentration of sodium carbonate appears to be about 2 to 3%, the amount of sodium carbonate solution carried by the fabric being about 80% of the weight of the fabric- The creping operation may consist, for example, in a treatment of the fabric with a hot aqueous soap solution, e. g., a treatment with a 0.5%

solution of soap at a temperature of at least '45 80 C., and preferably just below boiling temperature. A satisfactory degree of shrinkage can be produced by subjecting fabrics treated in accordance with this invention to treatment for periods of less than one minute in such solutions. Since the steps of treating the fabric with a hydrolysing or saponifying agent, drying the fabric and washing the fabric also take only a very short time to carry out, the whole treatment of the fabric according to the new process can be effected as a continuous operation. Thus the fabric may be passed continuously through a vessel containing a solution of a hydrolysing or saponifying agent, thence between nip rollers to adjust the amount of solution retained by the fabric, thence through a hot chamber or in contact with a heated surface, thence into a washing bath, and finally into the crping bath.

The following examples illustrate the invention but are not to be regarded as limiting it in any substantially no tension.

The fabric is then led through warm water and finally into a soap solution maintained at about 99 C. The rate of travel of the fabric is adjusted so that it is in contact with this hot soap solution for a period of half a minute. An excellent crpe effect is obtained.

Example 2 A cellulose acetate fabric containing cellulose acetate yarns which have been highly twisted by one of the processes of the specifications mentioned above is padded with a 2% sodium carbonate solution and the amount of solution retained by the fabric adjusted to about of the weight of the fabric. The fabric is then led into a hot air chamber at 75 C. under minimum tension and is then passed directly into a crping bath consisting of a /2% soap solution maintained at about 99 C. The rate of travel of the fabric is adjusted so that the fabric is in contact with this hot soap solution for half a minute. An excellent crepe effect is obtained.

When using caustic soda and sodium carbonate in accordance with this invention there is usually a very rapid reduction in the lustre of the fabric as it passes through the creping bath. This result is apparently due to the fact that some sodium acetate is formed on the fabric, a conclusion which is supported by the fact that by padding the fabric with sodium acetate prior to creping a very rapid delustring is obtained during the creping operation. This property of sodium acetate appears to be shared by sodium, ammonium and potassium salts generally, e. g. sodium carbonate, sodium bicarbonate, sodium chloride and sodium nitrite, and also by some metal salts, e. g. barium chloride, and it is not a property which depends entirely on the use of a soap solution as the creping bath since substitution of a hot water bath produces similar results though generally to a lesser degree.

If it is desired to preserve the lustre of the fabric, some improvement may be effected by adopting the expedient of washing the fabric with warm water prior to the crping operation. A better method of preserving the lustre, however, is by the incorporation of salts and/or sugars in the creping bath. A very suitable salt is, for example, ammonium sulphate, whilst a suitable sugar is ordinary cane sugar.

Having described our invention, what we desire to secure by Letters Patent is:

1. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yarns of an organic ester of cellulose to over-all saponification to an extent insufficient substantially to affect the dye aflinity of said yarns, and thereafter treating the fabric with a creping bath.

2. Process for the production of fabrics exhibitin crepe effects, which comprises subjecting a fabric containing high twist yarns of an organic ester of cellulose to over-all saponification to an extent insufficient substantially to affect the dye affinity of said yarns by means of an aqueous saponifying bath, and thereafter treating the fabric, while it is still wet with the saponifying agent, with a creping bath.

3. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yarns of an organic ester of cellulose to over-all saponification by treatment with an aqueous saponifying bath followed by drying the fabric while it still contains some saponifying agent, the saponification being insuilicient substantially to affect the dye affinity of the material of the fabric, and after the drying step treating the fabric with a creping bath.

4. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yarns of an organic ester of cellulose to over-all saponification in an aqueous saponifying bath to an extent insufllelent substantially to affect the dye aflinity of said yarns, washing the fabric and subjecting it to a creping bath.

5. Process for the production of fabrics exhibiting crepe eifects, which comprises subjecting a fabric containing high twist yarns of cellulose acetate to over-all saponification to an extent insufficient substantially to affect the dye afllnity of said yarns, and thereafter treating the fabric with a creping bath.

6. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yams of cellulose acetate to over-all saponiflcatlon to an extent insuflicient substantially to afiect the dye affinity of said yarns by means of an aqueous saponifying bath, and thereafter treating the fabric, while it is still wet with the saponifying agent, with a creping bath.

7. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yarns of. cellulose acetate to over-all saponification by treatment with an aqueous saponifying bath followed by drying the fabric while it still contains some saponifying agent, the saponification being insui'ficient substantially to affect the dye affinity of the material of the fabric, and after the drying step treating the fabric with a creping bath.

8. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yarns of cellulose acetate to over-all saponification in an aqueous saponifying bath to an extent insufficient substantially to afiect the dye affinity of said yarns, washing the fabric and subjecting it to a creping bath.

9. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting a fabric containing high twist yarns of an organic ester of cellulose, to over-all saponiflcation to an extent causing a loss of weight of 1 to 5%, said saponiflcation being insuflicient substantially to affect the dye amnity of said yarns, and thereafter treating the fabric with a creping bath.

BERNARD JOSEPH FLANAGAN. ALBERT Pgtent No. 2,215,853.]

CERTIFICATE OF CORRECTION.

v r i June 5, 19in. w ERNABD JOSEPH FLANAGAN, ET AL. 7

It is" hereby eertified that ezfre'r appears in the printed specification of the above numbere dpa tent requiring correction .as fqllowsz Page 2, sec- 0nd column, line 2, for "1/2 soap" read l/2f{ soap--; and that the said Letters Patent shq'uld be read viith -fihie correction th erein that the same may conform to the recordof .the 0:156 in the Patent Office.

Signed and sealed. this 22nd da of July A. D. 19m.

Henry Van Arsdale,.

Aefing co'mniissidnen of Patents. 

